Angles and Their Measure

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Section 1.4.1 Day 1 Unit Circle
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Objectives

• After this lesson, you should be able to
• label the unit circle

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Definition
y
Unit Circle A circle with radius 1 and center at
the origin of a rectangular coordinate system.
x
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90

• 1. Fold circle into 90 angles
• Label quadrants
• Draw radii (Mark right side of x-axis darker)
• Label ordered pairs
• Label degrees from 0 to each interval
• Label the corresponding radian
• measure (use fraction always)

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Definition
y
Radian The length of the arc on the unit circle
above the angle. The length of this arc is a
measure of the angle in radians.
x
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Radians

• 1. Measure radius with Wikki Stix
• Measure one radian on arc of circle
• Continue process around circumference of circle
• Label radians from 0 rads to each interval

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45

• Measure 45 angles
• Label ordered pairs
• 3. Label degrees from 0 to each interval
• 4. Label the corresponding radian measure (use
  fraction always)

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30

• Measure 30 angles
• Label ordered pairs
• 3. Label degrees from 0 to each interval
• 4. Label the corresponding radian measure (use
  fraction always)

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60

• Measure 60 angles
• Label ordered pairs
• 3. Label degrees from 0 to each interval
• 4. Label the corresponding radian measure (use
  fraction always)

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Label each point on the circle graph in degrees
and radians.
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Assignment
1. WS (5.2A) 1-10 2. WS (5.2B) 1-21 3. WS
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